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目的测定食用油等油中的呋喃含量。方法将5 g油样密封于(540±5)mL瓶中,加入一定量呋喃(X),于65℃水浴加热1 h后测定其呋喃(Y)含量。选择离子流动管质谱(selected ion flow tube mass spectrometry,SIFT/MS)方法,以NO+为初始离子,测定油样密封瓶顶空中呋喃浓度,再据呋喃标准曲线定量密封瓶中油样的呋喃含量。结果所得标准曲线为:Y=29.55X+1.11(r~2=0.9867,n=6),其检测限和定量限分别为0.052 ng/g和0.063 ng/g。利用该标准曲线测定多种油,其中废弃餐用油(即各种类型的地沟油、煎炸老油等)呋喃含量为4.37~17.83 ng/g;大豆油、花生油、两种菜籽油、茶油、葵花油的呋喃含量均小于1 ng/g;两种冷榨橄榄油的呋喃含量分别为1.19和4.39 ng/g。结论该法可方便、快速、准确地测定油样中呋喃的含量,呋喃可以作为鉴伪食用油和废弃餐用油的特征性指标。
Objective To determine the content of furan in edible oils and other oils. Methods A 5 g oil sample was sealed in a (540 ± 5) mL flask, and a certain amount of furan (X) was added. The furan (Y) content was determined after being heated in a water bath at 65 ° C for 1 h. Selected ion flow tube mass spectrometry (SIFT / MS) method, with NO + as the initial ion, was used to determine the concentration of furan in the headspace of the oil-sealed bottle, and then the furan content of the oil-sealed samples was quantified by the furan standard curve. Results The standard curve obtained was: Y = 29.55X + 1.11 (r ~ 2 = 0.9867, n = 6). The limits of detection and limit of quantitation were 0.052 ng / g and 0.063 ng / g, respectively. A variety of oils were determined by this standard curve. The content of furan was 4.37 ~ 17.83 ng / g in waste cooking oil (ie, various types of cooking oil and frying oil); soybean oil, peanut oil, two kinds of rapeseed oil, The furan content of both tea oil and sunflower oil was less than 1 ng / g; the furan content of the two cold-pressed olive oils was 1.19 and 4.39 ng / g, respectively. Conclusion The method can be used to determine the content of furan in oil samples conveniently, rapidly and accurately, and furan can be used as the characteristic index to identify pseudo-edible oil and waste edible oil.